Comparative histology and immunohistochemistry of porcine versus human skin

Abstract

Comparative histology and immunohistochemistry of porcine versus human skinBackground. Porcine skin is increasingly being employed as a model of human skin in various research fields, including pharmacology, toxicology and immunology, with particular interest in percutaneous permeation and organ transplantation. Porcine skin shows several anatomical and physiological similarities, but also some differences, with human skin, but few in depth comparative studies are so far available. Ojectives. To study the immunohistochemical properties of normal porcine skin in comparison with human skin. Materials and methods. We performed a histological and immunohistochemical study on frozen and formalin-fixed, paraffin-embedded skin biopsies from domestic swine and normal human skin, using a panel of 93 monoclonal or polyclonal antibodies recognizing various human and porcine skin cell types or structures. Results. We found that several antibodies used to detect normal human skin cells showed equivalent immunoreactivity on normal porcine skin. However, some antibodies commonly used to detect human skin antigens remained unreactive on porcine skin. Conclusions. Our findings highlight the main immunohistochemical properties of porcine skin in comparison with those of human skin and provide a morphological and immunohistochemical basis useful to researchers using porcine skin.

The immunology of the porcine skin and its value as a model for human skin

“…Furthermore, when a measure less dependent of body site such as the dermal-epidermal thickness ratio is considered (10:1-13:1) the pig is again very similar to human (Meyer et al, 1978). Pig as well as human also shows developed rete-ridges and pars papillaris, and abundant subdermal fatty tissue (Debeer et al, 2013;Kong and Bhargava, 2011;Marquet et al, 2011;Montagna and Yun, 1964;Sullivan et al, 2001). In fact, fat and not fur/hair are the main insulation components of porcine and human skin.…”

“…Moreover, in pigs apocrine glands are distributed through the skin surface. Regarding histology and the protein and lipid compositions of the different layers, obvious similarities between both species have also been identified (Debeer et al, 2013). The lack of skin pigments in many breeds of pigs is also advantageous for dermal studies.…”

“…Several studies assessed the porcine skin using various approaches such as histology (Debeer et al, 2013;Montagna and Yun, 1964), confocal Raman microspectroscopy (Tfaili et al, 2012), and infrared spectroscopy (Kong and Bhargava, 2011). They showed that in pigs the stratum corneum (SC) thickness is 20-26 m, comparable to what is observed in humans.…”

“…The epidermis represents the most important component of the skin barrier function protecting the body, while the dermis provides strength and elasticity to that barrier with collagen and elastic fibers embedded in proteoglycans. Typically the thickness of the human epidermis varies between 60 and 100 m in most areas (up to 600 m in the plantar and palmar regions) (Debeer et al, 2013;Elias, 2007;Proksch et al, 2008;Rushmer et al, 1966;Wang and Sanders, 2005). The dermis accounts for most of the skin thickness with 0.6-3 mm.…”

“…Indeed its anatomy, physiology, and immune system share numerous similarities with human. Regarding the skin, the pig is also very similar to its human counterpart, as opposed to many "loose-skinned" animals such as mouse and rat (Table 1) (Debeer et al, 2013;Kong and Bhargava, 2011;Marquet et al, 2011;Montagna and Yun, 1964;Sullivan et al, 2001). The skin of rodents differs significantly from humans as it is loosely connected to the subcutaneous connective tissue (Kawamata et al, 2003).…”